PROJECT SUMMARY/ABSTRACT Sickle cell disease (SCD) is a group of heritable red blood cell disorders that primarily affect individuals who identify as Black or African-American. Other affected groups include those of Hispanic, southern European, Middle Eastern, and Asian Indian descent. The hallmark of SCD is the painful vaso-occlusive crisis (VOC), which is still not well understood or managed. This may result in delays in treatment, undertreatment, and unnecessary suffering. Because SCD primarily affects African-Americans and other minority groups, mistrust between patients and providers may put patients with SCD at increased risk of healthcare disparities, including reduced access to necessary pain management. For most patients, pain is managed at home, further contributing to underestimation by healthcare practitioners of the prevalence and impact of SCD pain. However, when patients in VOC present acutely, they have usually exhausted home care and outpatient therapies, thereby signaling the need for parenteral opioids. Using a retrospective cohort of 150 patients with SCD hospitalized at one urban academic medical center, the overall goal of this study is to develop methodology to characterize the sickle cell pain trajectory. Specifically, the aims are to (1) use latent class analysis to identify different patterns of pain trajectories during hospitalizations for sickle cell pain crisis and determine socio-demographic and clinical factors associated with the different pain trajectories; (2) describe the relationship between treatment management strategies and sickle cell pain scores during hospitalization; and (3) assess the relationship between different patterns of sickle cell pain trajectories and future readmission for sickle cell pain crisis. Results from the proposed study can then be used to develop prospective studies to better measure pain during hospitalizations or to identify factors that affect the pain trajectory, which can be used to target interventions or pain management approaches. In addition, better characterization of the pain trajectory and treatment of pain in SCD are especially urgent as efforts are made nationally to restrict access to opioids given the current crisis of abuse, addiction, and overdose. Patients experiencing severe and devastating pain, such as those with SCD, should not be made to suffer because they are denied necessary treatment.